EGU24-13246, updated on 09 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Recent methane surges reveal heightened emissions from tropical inundated areas

Xin Lin1, Shushi Peng2, Philippe Ciais1,3, Didier Hauglustaine1, Xin Lan4,5, Gang Liu2, Michel Ramonet1, Yi Xi1,2, Yi Yin6, Zhen Zhang7, and the Coauthors*
Xin Lin et al.
  • 1Laboratoire des Sciences du Climat et de l’Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
  • 2Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China
  • 3Climate and Atmosphere Research Center (CARE-C), The Cyprus Institute, Nicosia, Cyprus
  • 4Cooperative Institute for Research in Environmental Sciences of University of Colorado, Boulder, CO, USA
  • 5Global Monitoring Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA
  • 6Department of Environmental Studies, New York University, USA
  • 7National Tibetan Plateau Data Centre, State Key Laboratory of Tibetan Plateau Earth System, Environment and Resource, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
  • *A full list of authors appears at the end of the abstract

Record breaking atmospheric methane growth rates were observed in 2020 and 2021 (15.2±0.4 and 17.6±0.5 ppb yr-1), reaching their highest level since the commencement of ground-based observations in the early 1980s. Here we use an ensemble of atmospheric inversions informed by surface or satellite methane concentration observations to infer emission changes during these two years relative to 2019. We found a global increase of methane emissions of 20.3±9.9 Tg CH4 in 2020 and 24.8±3.1 Tg CH4 in 2021. The emission rise was dominated by tropical and boreal regions with inundated areas, as a result of elevated groundwater table. Strong, synchronous, and persistent emission increases occurred in regions such as the Niger River basin, the Congo basin, the Sudd swamp, the Ganges floodplains and Southeast Asian deltas and the Hudson Bay lowlands. These regions alone contributed about 70% and 60% of the net global increases in 2020 and 2021, respectively. Comparing our top-down estimates with simulation of wetland emissions by biogeochemical models, we find that the bottom-up models significantly underestimate the intra- and inter-annual variability of methane sources from tropical inundated areas. This discrepancy likely arises from the models’ limitations in accurately representing the dynamics of tropical wetland extents and the response of methane emissions to environmental changes. Our findings demonstrate the critical role of tropical inundated areas in the recent surge of methane emissions and highlight the value of integrating multiple data streams and modeling tools to better constrain tropical wetland emissions.


H. Bösch8,9, P. Bousquet1, F. Chevallier1, B. Dong2, C. Gerlein-Safdi10, S. Halder1, R. J. Parker8,9, B. Poulter11, T. Pu10, M. Remaud1, A. Runge12, M. Saunois1, R. L. Thompson13, Y. Yoshida14, B. Zheng15,16

How to cite: Lin, X., Peng, S., Ciais, P., Hauglustaine, D., Lan, X., Liu, G., Ramonet, M., Xi, Y., Yin, Y., and Zhang, Z. and the Coauthors: Recent methane surges reveal heightened emissions from tropical inundated areas, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13246,, 2024.